The purpose of this study is to develop a methodology for screening pregnant women for use of alcohol and other drugs, thereby improving the availability and accessibility of alcohol-related treatment and prevention services for this special population. Our specific aim is to evaluate the performance of a new screening instrument, the 4P's Plus, against a standardized diagnosis of substance abuse, dependence, or problem use, based on DSM-IV criteria, in a population of pregnant women who receive prenatal care through the Northern California Kaiser Permanente Medical Care Program (KPMCP). All pregnant women enrolled in prenatal care at two KPMCP sites will answer the five questions on the 4P's Plus via self-administration. Two groups will be defined based on results of the 4P's Plus: Subject group (n=1000) - women with a positive screen on the 4P's Plus Control group (n=1000) - a randomly selected group of women with a negative screen on the 4P's Plus. The hypothesis of this study is that the 4P's Plus will accurately identify those pregnant women at risk for the use of alcohol or illicit drugs, as documented through either a DSM-IV diagnosis of a substance use disorder or patient assessment confirms the patient has used alcohol or other drugs since pregnancy but does not meet DSM-IV criteria for Substance Dependence or Substance Abuse. This hypothesis will be tested by evaluating the validity of the 4P's Plus screening instrument through sensitivity and specificity analysis. Positive predictive value and negative predictive value also will be computed. Through this study, physicians and other prenatal care providers will be able to identify substance abusing pregnant women so as to refer them into appropriate services, ultimately improving pregnancy and child outcome.